Conventionally, a variety of resins have been used in semiconductor packages as sealing agents such as underfilling agents and overmolding agents. An underfilling agent is disposed between a substrate and an electronic component (for example, a semiconductor chip, resistor, capacitor, inductor, transistor, or the like) so as to connect the substrate to the electronic component. The electronic component and the substrate are electrically connected via solder bumps. Because the underfilling agent is filled by means of a capillary phenomenon between the substrate, the solder bumps and the electronic component, the underfilling agents generally have low viscosities. However, in order to ensure that the components are reliably connected, it is essential that following curing, the underfilling agent has an appropriate range for the module, coefficient of thermal expansion, and glass transition point (Tg). Peng Su et al. reported in the Journal of Electronic Materials, Vol. 28, No. 9, 1999, page 1017 that appropriate ranges are, for example, 7 to 20 GPa, 20 to 40 ppm, and 60 to 120° C. respectively.
In recent years, semiconductor packages have been subjected to three-dimensional integration in which semiconductor chips are laminated and wiring is carried out in the vertical direction. Semiconductor packages having a variety of structures in three dimensions have also appeared. For example, in a semiconductor package such as that shown in FIG. 1, a first electronic component (11) is electrically connected to a substrate (14) via solder bumps (13), and a second electronic component (12) disposed on the upper part of the first electronic component is electrically connected to the substrate by bonding wires (15). In this type of semiconductor package, because problems such as connection defects can occur if the edge of an underfilling agent (16) extends to where the bonding wire (15) contacts the substrate, the position of the edge must be precisely controlled by adjusting the fluidity of the underfilling agent.
Another solution is to use an overmolding agent to connect the substrate to the electronic component, as shown in FIG. 2. In the embodiment of FIG. 2, an electronic component (21) disposed on a substrate (24) via solder bumps (23) is covered by an overmolding agent (26). In order for the edge (261) of the overmolding agent (26) not to have an adverse effect on an element other than the substrate, such as a bonding wire, the position of edge (261) must be controlled.
In addition, semiconductor package resin compositions have been directly coated on semiconductor wafers before dicing into semiconductor chips in recent years in order to increase the efficiency of semiconductor chip production processes. U.S. Patent Application Publication No. US 2006/0194064 A1 describes a curable underfill encapsulant composition that is directly coated on a semiconductor wafer before the wafer is diced into individual chips. This underfilling agent is coated on a semiconductor wafer, B-stage solidification is carried out at a temperature of approximately 100° C. to approximately 150° C. before final complete curing, and a smooth, non-tacky solid coating is formed in order to dice the wafer into individual chips. The wafer is then diced into individual chips, a B-stage processed chip having an underfilling agent is disposed on a substrate in a state whereby this underfilling agent is adjacent to the substrate, and final complete curing is carried out at a second temperature, which is higher than the B-stage conversion temperature.